Brake power....... Not!

[heyiga]

I am getting a repeated problem with my brakes. Heres the story:

New discs and pads approx 2000 miles ago (standard set)
Brake fluid changed to 5.1 approx 6 weeks ago.
Full bleeding of brakes done at same time.

Problem is the 'feel' and bite keep fading gradually each time after the brakes are bled, and the car pulls to the left on hard brakes, and now I have to really push hard for anything to happen at all! The fluid level is fine, apart from bleeing them again, what might be causing this problem?

I don't know if it is relevant, but the handbrake is as much use as a chocolate fireguard.

Any suggestions?

Ian

[S3Swiss]

Not sure the poor h/brake and the other snags are connected - unless you have a weeping seal in a rear cylinder which is contaminating the shoes?
I'd start with the rears and if nothing untoward there - look closely at pistons in the front. Can't think of 1 fault that would give all the symptoms - sure someone will be along to solve the mystery shortly!

[GreenV8S]

Changing pads and bleeding the brakes will mean all the hydraulics move outside their normal operating range and are vulnerable to damage. It may well be that one of the master or slave cylinders has been damaged. It could also be a stuck slider on one of the front brakes (most likely the side that it is pulling away from) or something similar in the rear drum brake mechanism.

Are left and right brakes getting up to similar temperatures?

[heyiga]

Green V8, this maybe a silly question, but apart from driving the car hard for a while and then sticking my poor little finger on each disc, how do you tell if they are heating up differently?

Also, I have the brake shields fitted to the front wheels, so the only way to see the discs is to get the wheels off!

How do you tell if a slider is stuck?

[tvrgit]

Hi Ian

If a slider is stuck then the front brake won't be as efficient on that side. Over time, the pad on the piston side of the caliper will wear quite quickly, while the one on the other side hardly wears at all (the stuck slider means it's never pulled against the disk, see?)

It could also be that the slider is sticking AFTER you put the brakes on, and not releasing quickly enough - then the pad is held in contact with the disk and wears quicker than the one on the piston side. This will also heat the brake fluid and cause vapourisation and brake fade which then affects the pressure available through the rest of the system when you next press the pedal. This would tend to pull the car to that side when driving though.

Groping the caliper will give an idea if one side is doing more work than the other (do it very gingerly - if it is badly over heating it will take the skin off your finger!)